The diffraction of oblique surface waves, by a right-angle blend

We investigate the diffracted field that arises when an incident electromagnetic surface wave strikes the edge of a right-angle bend at an oblique angle. One face of the bend supports the surface wave and the other face is a perfect conductor. This diffraction problem is related to the scanning surface wave antennas. We treat two cases which correspond to the normal TM and TE surface waves respectively. The first case may be reduced to the two dimensional TM problem. The second ease involves a second order boundary condition and is exactly analyzed in detail. The effect of the obliquity on the reflection coefficient and on the radiation pattern in each case will be discussed.